The present invention relates to a method for the determination of ceruloplasmin activity and a reagent suitable therefor.
Ceruloplasmin, which is a glycoprotein enzyme containing copper, is one of plasma protein and is present in an .alpha..sub.2 -globulin fraction in a concentration of 0.5% on the basis of total serum. It has an activity to oxidize divalent iron into trivalent iron.
The determination of ceruloplasmin activity is useful for diagnosis of liver cirrhosis, chronic hepatitis, liver failure, Wilson's desease, etc.
Heretofore, as to the assay of ceruloplasmin, single radial diffusion method for the immunologic quantitation of proteins (SRID method) and colorimetric method using diamine oxidase are known. There are problems of time-consuming reaction (usually, more than 24 hours) and inaccuracy of results in the former method. The latter is a simpler method than the former, but the reaction rate is slow and it takes 15-30 minutes to complete the reaction. The blank reagent is colored during reaction because the reagent is unstable and therefor it cannot be applied to the usual automatic assay instrument.